Aircraft components and structural members come in a wide variety of complex shapes and sizes. Weight and strength considerations have led to construction technologies such as composite ply lay-up methodologies. In such methodologies, epoxy infused materials are layed up onto mandrels or similar structures and then subjected to curing procedures. Once cured, the composite plies are then removed. Although this procedure is well known and understood, it can generate significant challenges for the fabrication of components with complex shapes.
Such is the case with barrel shaped components. Components such as fuselage skins and stringers must commonly be laid up on complex mandrels composed of multiple rigid segments prior to curing. Once cured, these segments must be dismantled and removed in order to remove the composite barrel structure from the mandrel. Aircraft dimensional proportions, however, dictate that these rigid segments become heavy and commonly require large handling equipment to disassemble. Often design of these structures requires personnel to climb inside the mandrel to unfasten retaining bolts and guide the heavy equipment. This is highly undesirable as a host of time consuming and hazardous procedures must be implemented. Present mandrel configurations, therefore, contribute negatively to the production flow timing.
In addition, the multiple rigid segments utilized in present designs result in a plurality of joints, each of which representing a potential source of vacuum leaking. Vacuum leaks can result in defects in the laminate and possible scraping of the resultant part. Thus considerable time must be expelled to insure proper assembly and disassembly of the mandrel to insure proper joint sealing and to insure joint regions do not experience damage during disassembly.
It would therefore be highly desirable to have an aircraft barrel lay-up assembly that reduced the time and complexity of resultant composite component removal. It would additionally be highly desirable to have an aircraft barrel lay-up assembly that minimized the number of sealing joints so as to simplify joint sealing prior to vacuum applications.